The overall goal of the Mitogenic Signaling Networks project is the development of high level statistical and specific physico-chemical models that describe key features of mitogenic signaling networks activated by ErbB receptors and by oncogenic K-ras. Over the past 4 years we have made significant progress in developing models of ErbB family mitogenic signaling networks in a variety of cell types, including statistical and kinetic models describing the effects of increased expression of various ErbB family members. Over the next five years we will extend these models to include mitogenic signaling networks resulting from mutant isoforms of EGFR and K-Ras that are directly associated with poor prognosis in human cancers of the central nervous and respiratory systems. Models will be developed and tested at a variety of scales, including in vitro cell culture systems, murine xenografts, and mouse cancer models. In addition, due to the success of a pilot project funded from our current ICBP, we will extend these models to integrate transcriptional regulatory networks, providing a more global, quantitative model of cellular regulation in response to oncogenic mutation. Since therapeutic resistance is one of the hallmarks of lung and brain tumors driven by mutant EGFR and mutant Ras, in the next phase of this project we will quantify and model signaling and transcriptional network alterations resulting from treatment with a variety of therapeutics, including classical chemotherapeutics, targeted therapeutics, and radiation. The goal of this project is to understand adaptation mechanisms used by tumor cells in developing therapeutic resistance in order to target these adaptive mechanisms to revert resistance. Quantitative models of mitogenic signaling network responses to therapeutics will be applied to human tumors to test their ability to predict responsiveness of human tumors to selected chemotherapeutic agents. This project will facilitate the integration of mitogenic signaling network models with DNA damage response models developed in Project 2, leading to more integrated models of cellular regulatory networks.